[AndrewJ]

Gday Chris

Now I know its the 497EP

Nope, it is an Audiostar. Different beastie.

In your posted instructions you say to select the spf. But what about the rom file - does it need to be uploaded into Audiostar first,

No. The rom file is the raw Meade file. The spf file effectively grabs the rom file, then edits it to apply the changes so it can be uploaded.
Andrew